Optical characteristic measuring apparatus, method and recording medium

摘要

The object of the present invention is to provide apparatuses that enable to enlarge the range of modulation frequencies that modulate the variable wavelength light generated by the light source without prejudice to the measurement of optical characteristics. In order to achieve said object, a modified modulation frequency computing section 44 for computing modified modulation frequencies fi by multiplying by the initial modulation frequency fmin the value obtained by dividing the given phase value pi by the phase difference between the first phase phimin_i of the transmitted light resulting from the transmission through the DUT 30 of the incident light of the first wavelength lambdai modulated by the initial modulation frequency fmin and the second phase phimin_i+1 of the transmitted light resulting from the transmission through the DUT 30 of the incident light of the second wavelength lambdai+1 modulated by the initial modulation frequency fmin, and a modified modulation frequency setting section 46 for setting the modified modulation frequency fi as the frequency of the modulating signal are included so that the frequencies for modulating the incident light may be wider in range than the initial modulation frequency fmin and that the phase difference between phii and phii+1 may be kept at a value equal to or below the given phase value pi, and thus the precision of measuring phase differences can be enhanced.